#ifndef __PROCESS_POOL_HPP__
#define __PROCESS_POOL_HPP__

#include <iostream>
#include <vector>
#include <unistd.h>
#include <cstdlib>
#include<sys/wait.h>
#include "Task.hpp"

//先描述
class Channel
{
public:
    Channel(int fd,pid_t id) : _wfd(fd), _subid(id)
    {
        _name="channel-"+std::to_string(_wfd)+"-"+std::to_string(_subid);
    }
    ~Channel() 
    {
    }
    void Send(int code)
    {
        int n=write(_wfd,&code,sizeof(code));
        (void)n; //
    }
    void Close()
    {
        close(_wfd);
    }
    void Wait()
    {
        pid_t rid=waitpid(_subid,nullptr,0);
        (void)rid;
    }
    int Fd() { return _wfd; }
    pid_t SubId() { return _subid; }
    std::string Name() { return _name; }
private:
    int _wfd;
    pid_t _subid;
    std::string _name;
};

//在组织
class ChannelManager
{
public:
    ChannelManager():_next(0)
    {
    }
    void Insert(int wfd,pid_t subid)
    {
        _channels.emplace_back(wfd,subid);
        //Channel c(wfd,subid);
        //_channels.push_back(std::move(c));
    }
    Channel &Select()
    {
        auto &c=_channels[_next];
        _next++;
        _next %=_channels.size();
        return c;
    }
    void PrintChannel()
    {
        for(auto &channel : _channels)
        {
            std::cout<<channel.Name()<<std::endl;
        }
    }
    void StopSubProcess()
    {
        for(auto &channel : _channels)
        {
            channel.Close();
            std::cout<<"关闭:"<<channel.Name()<<std::endl;
        }
    }
    void WaitSubProcess()
    {
        for(auto &channel : _channels)
        {
            channel.Wait();
            std::cout<<"回收:"<<channel.Name()<<std::endl;
        }
    }
    ~ChannelManager() {}

private:
    std::vector<Channel> _channels;
    int _next;
};

const int gdefaultnum=5;

class ProcessPool
{
    public:
    ProcessPool(int num) : _process_num(num) 
    {
        _tm.Register(PrintLog);
        _tm.Register(Download);
        _tm.Register(Upload);
    }
    void Work(int rfd)
    {
        while(true)
        {
            int code=0;
            ssize_t n=read(rfd,&code,sizeof(code));
            if(n>0)
            {
                if(n!=sizeof(code))
                {
                    continue;
                }
                std::cout<<"子进程["<<getpid()<<"]收到一个任务码:"<<code<<std::endl;
                _tm.Execute(code);
            }
            else if(n==0)
            {
                std::cout<<"子进程退出"<<std::endl;
                break;
            }
            else
            {
                std::cout<<"读取错误"<<std::endl;
                break;
            }
        }
    }
    bool Start()
    {
 
        for(int i=0;i<_process_num;i++)
        {
            //1.创建管道
            int pipefd[2]={0};
            int n=pipe(pipefd);
            if(n<0) 
                return false;

            //2.创建子进程
            pid_t subid=fork();
            if(subid<0)   
                return false;
            else if(subid==0)
            {
                //子进程
                //3.关闭不需要的文件描述符
                close(pipefd[1]);
                Work(pipefd[0]); //
                close(pipefd[0]);
                exit(0);
            }
            else
            {
                //父进程
                //3.关闭不需要的文件描述符
                close(pipefd[0]); //写端pipefd[1]
                _cm.Insert(pipefd[1],subid);
                //wfd,subid
            }
        }
        return true;
    }
    void Debug()
    {
        _cm.PrintChannel();
    }
    void Run()
    {
        //1.选择一个任务
        int taskcode=_tm.Code();

        //2.选择一个信道（子进程），负载均衡的选择一个子进程，完成任务
        auto &c=_cm.Select();
        std::cout<<"选择一个子进程："<<c.Name()<<std::endl;
        //2.发送任务
        c.Send(taskcode); 
        std::cout<<"发送了一个任务码："<< taskcode <<std::endl;

    }
    void Stop()
    {
        //关闭父进程所有的wfd即可
        _cm.StopSubProcess();
        //回收所有子进程
        _cm.WaitSubProcess();
    }
    ~ProcessPool() 
    {
    }
private:
    ChannelManager _cm;
    int _process_num;
    TaskManager _tm;
};

#endif